In recent years, for diagnosing body tissues, optical coherent tomography (OCT) apparatuses which are capable of obtaining optical information about insides of tissues are proposed, as well as imaging apparatuses for obtaining optical information about conditions of the surfaces of such tissues. Optical coherent tomography apparatuses employ techniques for dividing low-coherence light into two parts, further directing one part of the light toward an object to be measured and causing the returned scattering light modified with phase information about the object to interfere with the other part of light, further obtaining the phase information about the object from information about the intensity of the interfering light and, further, imaging the measured portion of the object (See Patent Document 1).